The FDA announced a formal regulatory approach to speed approval of bespoke, patient‑specific therapies for rare and life‑threatening conditions. Agency officials outlined a “plausible mechanism” roadmap that would allow decisions to be based on mechanistic lab data paired with limited clinical or natural history evidence. The proposal builds on the Baby KJ custom gene‑editing case and was presented in a New England Journal of Medicine perspective authored by FDA leaders. This pathway intends to create clearer expectations for developers of individualized gene‑editing and other highly tailored biologics while preserving safety review standards. Stakeholders will watch guidance details — including evidence thresholds and post‑approval monitoring — that will determine how broadly the pathway can be used without compromising reproducibility or patient protection.